1. Field of the Invention
The present invention relates to the development of tools for specific purposes. More specifically, the present invention relates to tools which aid in the removal of impellers from their respective shafts. The present invention is a device that holds the impeller in a fixed position relative to a substantially immovable structure, such as the impeller housing, while the shaft is threadedly disengaged from the impeller.
2. Description of the Prior Art
Methods for removing impellers from their respective shafts have been developed over the years. The most common method is to hold the shaft steady and strike the vanes or blades of the impeller, thereby causing the impeller to threadibly disengage the shaft. Though this method is effective, there are a number of problems that arise.
First, by striking the impeller vane with a hammer, there is a great likelihood that the vane may bend, break or fracture. A small fracture of an impeller vane can be magnified many times by the extreme forces it will encounter during operation. As a result, a fracture or a break of the impeller vane renders the vane and pump inoperable due to balance problems while rendering the mechanical seal inoperable due to alignment. This usually results in the ruining of the mechanical seal. Repairs associated with mechanical seals are very expensive. These occurrences are more likely to occur in pumps which operate at high flow rates and high pressures. Inoperable pumps prolong the down-time of any process and can add considerably to the operating cost of a fluid system.
Not only can the impeller be fractured by such rough handling, but flying fragments from striking the vane can injure a person nearby. Striking the impeller vane is potentially harmful to both the individual and to the equipment. Thus, there is a hazard associated with the removal of an impeller vane should one follow this practice.
Removing an impeller from its shaft can also take a considerable amount of time in that an individual can not obtain the leverage necessary to remove the impeller simply by striking it with a hammer or other heavy object. Even when the impeller is struck by a large hammer, the force is often insufficient to loosen the impeller from the shaft in any rapid fashion.
The reason that the impeller may be difficult to remove can be attributed to a number of reasons. The impeller and shaft may have corroded together due to their continual contact with fluids such as water and corrosive chemicals. As a result, the impeller may be very difficult to remove. The simple striking of the impeller vane is often insufficient to overcome the adhesive forces that result from corrosion deposits and fused threads.
In addition to any corrosive deposits that may have formed, one must overcome the initial torque applied to the impeller when it was installed on the impeller shaft. In order to avoid catastrophic failure of an pump during operation, the impeller needs to be strongly threaded to the impeller shaft. Moreoever, during operation, the impeller may be subject to large stresses. The stresses encountered during operation will force the impeller still further onto the impeller shaft. Both of these causes hinder removal of the impeller when necessary. Regardless of other causes, the sheer magnitude of these two forces render removal of the impeller from its shaft a difficult process.
The present invention is a device that can hold an impeller in a fixed position while the shaft is rotated. The individual need only apply leverage to the shaft via a gripping tool with a long handle. By rotating the shaft, the impeller is protected from fracture damage. Moreover, the impeller may be removed rapidly from the shaft, because an individual may apply a force directly thereto.